Key Issues
Tracing the Historical Roots of Health Inequity Among People With Intellectual and Developmental Disabilities in the United States: Impact of Models, Advocacy, Legislation, and International Context
Gloria L. Krahn PhD, MPH
Summary
How disability is understood has evolved over the past two centuries, with differing models of disability influencing legislation that has allocated increasing rights and resources to people with disabilities across time. Public health has played and will continue to play a central role in affecting the well-being of people with IDD. The responsibility for population-level data on the health and well-being of this population resides squarely with public health. Planning for the inclusion of people with IDD is needed in programs for preventive screening, infectious and chronic disease prevention and management, emergency preparedness, and messaging for health promotion campaigns. Finally, public health is critical to policy planning that relies on accurate prevalence and health status data. These actions can change the fate of people with IDD from being invisible to being visible and valued.
Rosemary was born in 1918 as the eldest daughter of a large, sports-loving family in the northeastern United States. Delays in her development became increasingly evident as she aged. At that time, public schools were not required to enroll children with conditions that would later become known as IDD. Professionals often recommended institutionalizing children with disabilities as the best option, with families having little contact with their “forgotten” children. Even if children with IDD were raised within the family, the stigma attached to having a child with IDD meant that their existence was often private. Rosemary’s family had the financial resources for special boarding schools and kept her in their family. As a young adult her challenging behaviors increased and on the advice of professionals, she underwent lobotomy surgery to reduce her depression and aggression. The surgery failed drastically, altering her personality and destroying most of her ability to walk and talk. As a result, she was institutionalized for the rest of her life.
This family story was not uncommon during that era: the story of difficult choices in the face of social stigma, no public education for children with IDD, few resources, and untested interventions. What was unusual was that the members of this family, the Joseph P. Kennedy family, leveraged their experiences to bring national attention and resources to the lives of all people with developmental disabilities (DD). Initiated during the Kennedy administration, significant legislation was passed to build an infrastructure for improved community-based research (Public Law 87-838 in 1962), training, and services (Public Law 88-164 in 1963) for people with IDD. Eunice Kennedy Shriver went on to found Special Olympics in 1968 and remained engaged with it for the next four decades.
How disability is understood influences how it is approached; models and approaches to disability have changed dramatically over time. Public health has embraced different views of disability historically, and at times actions intended to protect the public’s welfare egregiously violated individual rights of people with disabilities.
People with IDD continue to experience significant health inequities that are in part related to historical discrimination.2–6 These inequities remain largely unmeasured and unaddressed. Until recently, the health and well-being of people with disabilities, particularly IDD, have been invisible in public health data and programs.7–9 To illustrate, only in 2009 with the passage of the Affordable Care Act were federal data systems required to assess disability status when investigating health disparities. This provided a foothold for improved data to document disability-related inequities, although not with the specificity needed to improve data on IDD. The National Institutes of Health finally recognized people with disabilities as a health disparity population in 2023,10 providing access to additional research funding.
My purpose here is to provide public health readers with a brief history on IDD in the United States. I use a framework that considers the prevailing models of disability over time, the power of advocacy in effecting change, the importance of legislation for systemic change, and the international context wherein conceptualizations of the United Nations (UN) and World Health Organization (WHO) have paralleled or presaged views in the United States.
Several caveats should be noted. First, any effort to review a topic this vast necessarily omits many important events; I apologize for all such omissions. The intent is to provide a broad-stroke understanding of disability history from a public health perspective. Second, the perspective shifts discussed have been slow to spread, and their uptake has not been uniform across social sectors. Third, this article oversimplifies its presentation of primarily “mainstream” American perceptions and omits important intercultural nuances. Finally, although the term “mental retardation” was the formal term for almost a century, it is now offensive to many people and intellectual disability is used throughout.
Terminology can be confusing. People with IDD are a subgroup within the larger disability population. Intellectual disability is diagnostically categorized as a subgroup within developmental disabilities,11 although people with intellectual disability may not always meet the criteria for the federal definition of developmental disabilities requiring limitations in multiple areas.12 IDD varies along a continuum of severity. Most people with IDD experience milder forms in which the cause may be unknown; more severe forms are often part of a neurological or genetic syndrome. Environmental factors including nutrition, education, social interactions, and hazardous exposures also influence severity.13,14
Definitions of intellectual disability have been fairly consistent over the past century, with the following three criteria being used: (1) significant limitations in intellectual functioning, (2) limitations in adaptive behavior, and (3) origination before the age of 22 years.11,15 Intellectual disability and developmental disabilities are anticipated to be lifelong. Definitions of developmental disabilities5 and disabilities in general16 have been more variable. Definitions of developmental disabilities among children have historically been based on medical diagnoses. Conversely, the federal definition of developmental disabilities (as of 2000) requires significant functional limitations in at least three life areas and onset before the age of 22 years. Estimates of autism prevalence demonstrate dramatic increases over time, from two to four per 10 000 in the 1960s17 to current estimates of 322 per 10 000.18 This increase is at least partly because of increased attention to detection, diagnosis substitutions from intellectual disability, and less severe symptoms needed for current diagnosis.
The decrease in 1973 in the cut-point for IQ from 85 to 70 (one to two standard deviations below the mean)19 reduced the estimated prevalence of intellectual disability from about 3% to 4% to 1% to 2%.20,21 Approximately 9% of children and 2% to 4% of adults experience developmental disabilities22,23 (and up to 16% of children when attention deficit disorder and learning disabilities are included24). From 9% to 22% of adults experience disabilities generally depending on age, case definition, and data collection method.25
THE AGE OF SCIENCE
At the beginning of the 20th century, confidence in science and scientific expertise increasingly shaped the worldviews of policymakers in the United States.26 Before the mid-19th century, a charity approach to disability prevailed whereby assistance for people with IDD was distributed as charity at the discretion of those in power, often religious organizations. Excellent historical accounts that include this early period are available.27,28
The Medical Model
The medical model views disability as pathology of the individual; professionals diagnose disability and make treatment decisions with a focus on classification, cure, and rehabilitation. When efforts failed, this view often led to removal of the person from society through institutionalization or relegation to “life in the shadows.” Through much of the 20th century, public health regarded disability almost exclusively as a negative outcome to prevent and took little responsibility for the health and well-being of people with existing disabilities. This began to change only in the late 1980s,29 when the US Centers for Disease Control and Prevention (CDC) began to consider disability not only as a pathology but as a demographic characteristic that identified a segment of the population. The CDC began promoting the health of people with existing disabilities, collecting disability data, and establishing a network of state offices on disability and health.30
Institutionalization
As early as the mid-1800s, residential schools were established for the education of children with IDD. Institutionalization of children with disabilities became more popular, particularly as children aged and their care and behaviors became more challenging for families. These “schools” or “hospitals,” directed by physicians and using special education practices, were initially considered successful. But as the number of residents grew and costs increased, the model shifted from an educational focus to one of segregation and economization.
As early as 1866 at the opening of yet another institution, early advocate of special schools Samuel Gridley Howe warned that segregation from families and communities would “threaten to cause real asylums to grow out of them, and to engender other evils.”31(p38) People with disabilities were considered a burden on society, with some institutions established as self-sustaining farm compounds that relied on the “free” labor of residents.32 Residents lived their entire lives from early childhood in institutions, receiving little nurturing, education, or socialization. True to prediction, conditions deteriorated dreadfully in many institutions. Early warnings went unheeded until a 1972 media exposé of Willowbrook Hospital shocked the nation.33 Video footage of wailing people crowded into a room, some naked and smeared in feces, added impetus to deinstitutionalize residents and support them in communities. In the 1970s, disability scholar Wolf Wolfensberger documented this shift from institutions as “schools” and “hospitals” to “asylums” that housed and segregated the “deviants” from society.32
Eugenics
The early decades of the 20th century witnessed wider social embrace of the scientific method and biological determinism, along with the Progressive Era movement that called for increased social and political reforms to address the social problems accompanying rapid industrialization, urbanization, and immigration.34 This context contributed to eugenics practices in the United States and elsewhere intended to improve the human race. E. R. Johnstone, a pioneering American leader in psychological assessment and developmental disabilities, illustrated this view in 1911: heredity must claim by far the largest part of our attention if we are to check the stream of the feebleminded which is undoubtedly growing from year to year.35(p91)
In the landmark legal case of Buck v Bell in 1927, the US Supreme Court upheld the right of the state to involuntarily sterilize 18-year-old Carrie Buck, who had been institutionalized after becoming pregnant. Its ruling was as follows: It is better for all the world if, instead of waiting to execute degenerate offspring for crime or to let them starve for their imbecility, society can prevent those who are manifestly unfit from continuing their kind.36
Subsequent investigation refuted that Buck or her daughter experienced IDD and attributed her pregnancy to sexual assault while in foster care.37 Importantly, eugenics laws contributed to an estimated 70 000 involuntary sterilizations of disabled, poor, or immigrant women in this country and still exist in 31 states and the District of Columbia.38,39
THE POWER OF FAMILY AND SELF-ADVOCACY
Despite many people with IDD being institutionalized, many more were raised by their families. During the 1940s and 1950s, families were increasingly dismayed with institutional options and began organizing to advocate for more research and community-based services.
Functional Model of Disability
A functional model of disability was emerging at this time. As with the medical model, the functional model views limitations as being part of the individual but differs in focusing less on the specific diagnosis and more on the nature and severity of the limitations. Those determining disability are the professional (e.g., program eligibility) as well as the family and the person. A functional model of disability is reflected in many of the legislative acts passed during the 1960s and 1970s. For example, the federal definition of developmental disabilities shifted from one determined primarily by diagnoses in 1963 to one determined by functional limitations in later years. A functional model also underlies current survey assessments of disability such as the National Health Interview Survey,40 the American Community Survey,41 and the Behavioral Risk Factor Surveillance System.42 In these surveys, disability status is determined by individuals’ self-reports of significant functional limitations in learning, mobility, vision, hearing, self-care, or independent activities.
The Kennedy Family and the National Arc
Two family organizations that shaped IDD history in the second half of the 20th century were the Kennedy family and the Arc (previously Association for Retarded Citizens). Both organizations were founded by family members in the late 1940s to early 1950s, and both were powerful policy advocates for people with IDD regardless of condition.43,44 Other condition-specific organizations (e.g., for Down syndrome, cerebral palsy) advocated for specific diagnostic groups. The Kennedy Foundation and the Arc provided leadership in establishing direction and funding for research and community-based service programs. The Arc established local employment workshops for adults with IDD, whereas the Kennedy Foundation focused on sport, fitness, and health, establishing Special Olympics in 1968. In 1999, Special Olympics was instrumental in bringing the attention of the US surgeon general to the health of people with IDD, resulting in the seminal report Closing the Gap: A National Blueprint to Improve the Health of Persons with Mental Retardation.7
Transformation of the legislative landscape for IDD in the United States began with the presidency of John F. Kennedy in 1960. With IDD as one of its priorities, his administration initiated a series of legislative acts that have enjoyed bipartisan support for decades. These measures included creation of the National Institute of Child Health and Human Development for research on IDD, construction of University Affiliated Facilities for training (now University Centers for Excellence in Developmental Disabilities), state developmental disability planning councils, affirmative action in employment, state protection and advocacy systems for legal protection of rights of people with developmental disabilities, free and appropriate public education for all children with disabilities, and centers for independent living.
Self-Advocacy for Disability Rights
In the late 1960s and 1970s, adults with disabilities began actively and radically advocating for equal rights, opportunities to live in communities, and greater control over their lives. Disability rights movements were also gaining force in Europe, Canada, and Australia. As with the civil rights movement, the disability movement pushed for rights to access public buildings, education, employment, transportation, and housing. “The Rolling Quads” at the University of California, Berkeley epitomized this movement in the United States. In 1977, advocates staged a monthlong occupation of 10 federal buildings across the country to protest delays in the signing of federal legislation to ensure disability access to public buildings.45,46
Similar grassroots organizing in 1990 included a 60-person “capitol crawl” up the 83 stone steps of the capitol building to demonstrate the inaccessibility of public buildings and press for signing of the Americans with Disabilities Act. This legislation protects against discrimination based on having or being regarded as having a disability, with the 2008 amendment to the act qualifying the “regarded as” clause. The landmark Supreme Court ruling in Olmstead v L.C.47 established that unnecessary segregation of individuals with disabilities in institutions rather than in integrated, community settings is discriminatory. This finally closed the loop after more than a century and a half of institutionalization of people with disabilities.
Social Model of Disability
Advocates decisively rejected a medical view of disability and replaced it with a view that considered the greatest causes of disability to be the barriers associated with societal structures, environments, and social attitudes. Originating in the United Kingdom with the Union of the Physically Impaired Against Segregation,48 this view was dubbed the “social model” of disability in 1983.49 The social model distinguishes between “impairment” that is part of the body and “disability” that is the experience of disadvantage and restriction that excludes people with impairments from mainstream activities. The social model of disability challenges the power structure of a medical model, makes people the designators of their disability, and locates disability in the environment in which people live. The social model changes the question “what is wrong with you?” to “what is wrong with your setting?” The model quickly became the dominant model within the disability community in many countries.
INTERNATIONAL VIEWS ON DISABILITY
The UN was formed at the close of World War II, with an early act being the Universal Declaration of Human Rights in 1948.50 Influenced by advocacy and the social model of disability, the UN declared 1981 as the International Year of Disabled Persons, followed by the Program of Action in 1982.51 Since then, the UN and WHO have taken proactive stances on advancing the human rights and social inclusion of people with disabilities.9
Interactional Models
In 2001, WHO released the International Classification of Functioning, Disability and Health (ICF), a biopsychosocial framework of disability that integrates the medical model and the social model.52 The framework brings together environment, personal characteristics, and health conditions to understand an individual’s functioning, activities and participation in society. According to the ICF, disability is determined by the individual and results at the interaction of people’s condition and their environment. The ICF model has become dominant in many high-resource countries and influenced subsequent UN and WHO reports. After more than 25 years of use, researchers and people with disabilities have called for revisions to the ICF.53–55 In 2018, Mitra proposed the human development model, a capabilities model that incorporates resources into an integrated framework of disability.56
Convention on the Rights of Persons With Disabilities
In the early 21st century, the UN specifically extended recognition of human rights to people with disabilities. The purpose of the Convention on the Rights of Persons with Disabilities (CRPD) is to promote, protect, and ensure the full and equal enjoyment of all human rights and fundamental freedoms by all persons with disabilities and promote respect for their inherent dignity.”57
It emphasizes inclusion, nondiscrimination, and accessibility, specifically recognizing these rights for women and children with disabilities.
Importantly, the CRPD ties the well-being of people with disabilities to economic development goals, arguing that inclusion of these individuals is essential for overall economic development. The CRPD was adopted by the UN General Assembly in 2006, and as of 2025 it had been ratified by 191 countries. The United States is among a handful of member countries that have not ratified the CRPD,58 ostensibly for reasons of sovereignty. In the case of most high-resource countries, the CRPD is a framework for action and accountability on human rights and protection from discrimination against people with disabilities. It is having a significant impact globally on full inclusion of people with disabilities, albeit less so in the United States.
Human Rights Model
The CRPD is ushering in what some scholars regard as an emerging human rights model of disability.59–61 This model is premised on the right of all people to human dignity without consideration of impairment. As with the social model, it assumes that people are designators of their disability identity. In this model, human rights are upheld when society addresses people’s civil and political rights as well as their economic, social, and cultural rights, including supports needed to experience these rights. The addition of economic, social, and cultural rights recognizes the close relationship between disability and poverty,62 including the right to participate in research that has historically excluded “vulnerable” groups such as people with IDD.63
UN and WHO Reports
UN and WHO reports summarize findings across all disabilities and specifically include people with IDD.
World Report on Disability. In 2011, WHO and the World Bank published the World Report on Disability64 to draw the attention of all countries to the 15% of people who live with disabilities globally. For the first time, WHO provided data on the prevalence and health status of this population and called for better data, policies, and programs. Of note, this report reflected a social model of disability, focusing on the burden placed on people with disabilities by how society functions rather than the burden placed on society by people with disabilities.
UN Disability and Development Report. The Sustainable Development Goals of the UN 2030 agenda served as the framework for the Disability and Development Report—Realizing the SDGs by, for and With Persons with Disabilities.62 This report documents for the first time country-level statistics related to the Sustainable Development Goals and people with disabilities.
Global Report on Health Equity for Persons with Disabilities. Grounded in the right to the highest attainable standards of health, WHO’s 2022 Global Report on Health Equity for Persons with Disabilities65 updates health inequities and identifies 40 actions for countries to take. Primary strategies are inclusion of people with disabilities in all health planning, empowering people with disabilities, and monitoring outcomes. The launch of an implementation plan followed in 2025,66 with the plan emphasizing leadership by people with disabilities and prioritizing disability-inclusive health, inclusive health systems, and strengthening of data.
CURRENT ISSUES AND FUTURE DIRECTIONS
For decades, the need for timely access to affordable, high-quality health care for people with IDD and other disabilities has been recognized but unmet.7,8 Competencies for serving people with disabilities have been outlined for health care and public health professionals.67,68 Ableism, discriminatory presumptions and practices of health care and public health toward people with disabilities (including professionals with disabilities), requires specific attention to improve care.69,70 The intersection of disability with other marginalized identities such as race and sexual orientation creates compounded disparities in care.71
Data create visibility and impetus for change. Health data on people with disabilities overall have improved dramatically in the past decade, in part in response to the Affordable Care Act. Greater standardization and alignment of definitions of disability are now being called for.15,72–74 A debate centers on who designates disability status and how to take into account people with self-perceived disabilities who are not recorded in current approaches.16 At the core of this debate is “what model of disability should underlie disability identification?”
In contrast, health data on people with IDD are grossly inadequate to inform policy or program planning.75 Problems include that many people living in group homes or institutions are not included in surveys, most major data sets do not allow for identification with IDD, and the only national survey on the health needs of this population dates to 1994–1995.12,76 Substantive efforts are under way to improve health data on people with IDD, including the Special Olympics Healthy Athletes Screening,77 the National Core Indicators data set,78 multistate Medicaid analyses of administrative data in select states,79–83 and the IDD Counts! initiative (a federal interagency collaboration that is implementing a roadmap for health equity data for 2020–2030). The 2019 reauthorization of the Patient Centered Outcomes Research Institute mandated that people with IDD be added as a priority population to patient-centered outcome research. This is bringing much-needed attention and funding to understanding the health of people with IDD. Sustained and concerted future efforts are needed to improve data as outlined in the IDD Counts! roadmap.84
A popular definition of health is that of WHO (outlined in 1948): “a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity.”85 Scholars have noted the limitations of this static and idealized definition and called for a redefinition of health.86–88 As an extension of the WHO definition, a revised definition has been proposed: “Health is the dynamic balance of physical, mental, social, and existential well-being in adapting to conditions of life and the environment.”89(p3) This definition reflects a more contemporary, dynamic conceptualization of what it means to be healthy and includes people living with disabilities and chronic health conditions. As modeled by Mitra,56 reducing health inequities requires anticipating needed support and resources related to aging parents and caregivers and addressing the current crisis in direct support professionals.90
From segregation to inclusion, people with disabilities are demanding to realize their right to fully participate in society. The CRPD outlined countries’ obligations for full inclusion and monitoring of its implementation. Inclusion remains a key strategy for exercising human rights and promoting the health and well-being of people with disabilities.
Technology and social media have opened the world in new ways to people with IDD. Videoconferencing, texting, and telehealth facilitate health care access; apps support accessible way-finding; and language models such as ChatGPT simplify translation of complex material. Notwithstanding cautions about possible biases and misinformation with current platforms, artificial intelligence holds promise for people with IDD in terms of access to health care and information, support for decision making, and promotion of greater autonomy.
ACKNOWLEDGMENTS
Special Olympics Health activities are supported by many sources, including in the United States by Grant Number NU27DD000021 from the Centers for Disease Control and Prevention of the US Department of Health and Human Services, with $18.1 M (64%) financed with US Federal funds and $10.2 M (36%) supported by non-federal sources.
These contents are solely the responsibility of the authors and do not necessarily represent the official views of the Centers for Disease Control and Prevention or the Department of Health and Human Services.
About the Author
Dr. Gloria L. Krahn, PhD, MPH is a leading disability researcher, public health expert, and retired Oregon State University professor.